Great link!
https://spin.atomicobject.com/2016/07/06/time-zones-offsets/
"Given a local time and an offset, you can know UTC time, but you do
not know which time zone you’re in (because multiple timezones have
the same offset)."
So, given a time zone you can know the offset (Google it, for example)..
Then, given the time zone and the local time, you can know UTC.
If orgmode gets the UTC there is not ambiguity.
But, that would mean that the offset related to the different time
zones must be downloaded and updated from some site.
As you said before, that offset can change. For example, peninsular
Spain has the same time as Berlin, but as this doesn't make much
sense, it could change, so updates would be necessary.
I have been thinking about how I would use this feature. So use cases
appeared, which arose some doubts about how to use this feature, and an
opinion for the Poll surged:
If I wanted to assist to a "Mastering Emacs book club" meeting in
America/Vancouver, while living in Spain: Doubt: Should I use local time
of America/Vancouver to schedule the meeting?. Like: [2024-02-04 12:00
@America/Vancouver] (I don't like space before the @, for the Poll).
1. Doubt: I suppose my agenda timestamp would be: [2024-02-04 do.
21:00]. (Spain local time). Correct?
2. If I went on vacation to Brasília, my agenda timestamp should change
to: [2024-02-04 do. 17:00]. (Brasília local time).
Doubt: How must the local time zone be updated to get that timestamp
changed?
3. Back to Spain, I see that, for political reasons, Vancouver's winter
time-zone changed from UTC-8 to UTC-9.
Doubt: How would my tz database be updated?
Doubt: After updating the tz database, my agenda timestamp would
change automatically to [2024-02-04 do. 22:00]. Correct?
4. For the Poll: What would be the expected behavior if we used the UTC
offset? [2024-02-04 12:00 @-08,America/Vancouver]
- We should know beforehand the DST of Vancouver, or there would be
warnings. It seems more difficult for the user: maybe the "-08," should
be optional?
- Case 3: After updating the tz database we would get warnings too.
To correct those warnings, should the UTC offset be changed manually in
the timestamp?. If there were 35 meetings in Vancouver throughout the
year, to change all the UTC offsets could be non trivial for a normal
user: UTC of the summer and winter would differ.
[2024-09-04 12:00 @-07,America/Vancouver] should be changed to
[2024-09-04 12:00 @-08,America/Vancouver]
[2024-02-04 12:00 @-08,America/Vancouver] should be changed to
[2024-02-04 12:00 @-09,America/Vancouver]
